Axial compressive mechanical performance and bearing capacity design of bolted hollow spherical joints with double sleeves

This paper proposes a novel bolted hollow spherical joint with a dual-sleeve configuration consisting of a threaded sleeve and an installation sleeve. Five specimens are designed for axial compression tests, considering the thickness and radius of the hollow spherical shell, the length, thickness, and radius of the threaded sleeve, and the type of high-strength bolt. The failure mode, bearing capacity, and characteristics of the load-displacement and load-strain curves of the joints are analyzed. Finite element models of the joint under axial compression are established and validated against the test results. Systematic analyses are conducted on the axial compressive mechanical behavior of joints and the influence mechanisms of key parameters. Based on the test and finite element results, a design formula for the axial compressive capacity of the proposed joint is developed. The results indicate that as the ratio of the threaded sleeve diameter to the hollow spherical shell diameter ( d / D ) increases, the plastic spreading zone of the joint expands, and the ultimate axial compression capacity increases. Specifically, when d / D increases from 0.2 to 0.3, the ultimate axial compression capacity of the joint improves by approximately 11.5%. As the diameter-to-thickness ratio ( D / t ) of the hollow spherical shell increases, the plastic spreading zone of the joint shrinks, and the ultimate axial compression capacity continuously decreases. When D / t increases from 10 to 18, the ultimate axial compression capacity of the joint decreases by approximately 13%.